Comparison of the influence of boiler system operation changes on two kinds of dust collectors
①Change in the amount of flue gas produced by the boiler
Boiler bag filter: It is related to the filter bag. As long as the filter bag is not damaged, the outlet emission concentration of flue gas can achieve stable discharge, that is, less than 50mg plus 3, and the ash discharge method is automatically adjusted according to the system operation.
Electrostatic precipitator: The dust removal efficiency fluctuates greatly, and the smoke and dust emission concentration will fluctuate with the fluctuation of the grid voltage, and the emission will be unstable.
②The temperature change of boiler flue gas
Boiler bag filter: If the flue gas temperature is too low, it will condense, and at the same time, it may cause corrosion of the paste bag and the main steel structure; the flue gas temperature is too high and exceeds the allowable temperature of the filter material, which is easy to burn the bag. A bypass flue gas system is designed.
Electrostatic precipitator: If the flue gas temperature is too low, condensation will occur, which will not only cause corrosion of the steel structure of the main body, but also generate high-voltage creep-age inside the electric field; if the flue gas temperature is too high, the pole plate will be heated and deformed, and the specific resistance of the dust will increase. High, it is not easy to power on, thus affecting the efficiency of dust removal, and the impact is obvious.
③Air leakage in the boiler system
Boiler bag filter: For filter bags with poor oxygen resistance, it will affect the life of the filter bag, such as PPS filter material, so the oxygen content of the flue gas is controlled within 10%, but the dust removal efficiency is not affected.
Electrostatic precipitator: An increase in the amount of air leakage is equivalent to an increase in the wind speed of the electric field, and an increase in the wind speed of the electric field has an impact on the dust removal efficiency.
The pulse jet ash cleaning device uses compressed air as the source of ash cleaning gas and consists of a pulse valve, an air bag, and a blowing pipe. There are blowing pipes above each row of filter bags. Each blowing pipe is provided with ten blowing holes. Each blowing hole is aligned with the lower filter bag. One end of the blowing pipe is connected with the air bag, and the air bag enters the compressed air. Install a submerged pulse valve (with solenoid valve) on the air bag. The action of the solenoid valve drives the diaphragm of the pulse valve to make a short action. The compressed air in the air bag is sprayed into the filter bag from the small hole through the pulse solenoid valve instantaneously through the injection pipe, so that the filter bag expands outward. When the bag wall expands to the position , The large tension makes it subject to strong shock and vibration, and obtains reverse acceleration to begin to retract; but the dust layer attached to the surface of the filter bag is not affected by tension, and falls off the filter bag due to inertial force. Realize the dust removal of the filter bag. The electrical actuator of the pulse jet ash cleaning device is an electromagnetic pulse valve. By controlling the electromagnetic pulse valve, it achieves the purpose of controlling the pulse cleaning to proceed in an orderly manner. The pulse ash cleaning system takes electromagnetic pulse valve as the control object, uses programmable logic controller (PLC) as the core controller, and is equipped with pressure/differential pressure transmitter, platinum thermal resistance and other detection instruments for signal collection. The in-situ operation box is used for on-site debugging and operation, and is equipped with a host computer monitoring system for users to perform operation monitoring. The entire system is fully functional and stable.